1. Field of the Invention
The invention relates to novel 8-substituted-6,7-dihydro[5H]thiazolo[3,2-a]pyrimidinium and 9-substituted-5,6,7,8-tetrahydrothiazolo[3,2-a][1,3]diazepinium salts and 7-substituted-5,6-dihydroimidazo[2,1-b]thiazolium salts. The latter series of compounds have been generically disclosed as hypoglycemic agents and growth promotants in U.S. Pat. No. 3,954,784. It has now been found that all of the above salts are useful acaricidal agents and are particularly effective in destroying ticks and mites which tend to infect the skins of animals, especially sheep and cattle, and are therefore useful as ectoparasiticidal agents for treating such animals.
2. Description of the Prior Art
All stages in the life cycle of the tick tend to damage the skins of afflicted animals and thereby spoil the state of the skins, with the consequence for example, that cattle hides and sheep skins intended for manufacture of leather and sheep skin respectively, are reduced in quality. Furthermore, the ticks may facilitate the transmission of disease to the afflicted animal, and the general state of health and the quality of flesh of the animal may be detrimentally affected.
U.S. Pat. No. 3,954,784 discloses quaternary 7-substituted imidazo[2,1-b]thiazolium salts of the formula: ##STR1## wherein X.sub.1.sup..crclbar. is a pharmaceutically acceptable anion, preferably chloride or bromide ion; R.sub.1 is alkyl having from 12 to 18 carbon atoms; R.sub.2 is hydrogen or alkyl having from one to three carbon atoms; R.sub.3 is R.sub.2, phenyl or substituted phenyl wherein said substituent is dimethyl or dimethoxy; R.sub.2 and R.sub.3 taken together is tetramethylene and R.sub.4 and R.sub.5 may be hydrogen. The preparation and use of these compounds as hypoglycemic agents and growth promotants is also disclosed therein.